Evaporative cooler pads (for swamp coolers etc). You can buy they by the roll. Place around part of the run/coop, and wet down. The wind blowing through will cool them down. We have heat tolerant breeds, but it's still hot. We've hit 108 already (and triple digits numerous times) and things are hovering around 100 every day. Lots of different ways to keep them cool; watch them and you'll figure it out.